The head of the European Union's Greek task force said the haul of 946m euros compared with about 8bn euros in uncollected tax revenues.
However, Horst Reichenbach noted the amount was still more than double the 400m euros that had been targeted last year for Greece.
The task force is meant to help Greece reform and become more competitive.
The eurozone recently approved Greece's second bailout - worth 130bn euros - after first bailing out the debt-addled nation in 2010.
As part of these bailouts, Greece has passed several austerity packages to reform its public sector and claw back tax that has never been collected.
Tax evasion is generally considered to be widespread in Greece.
Mr Reichenbach leads a group of about 45 officials who visit Greece occasionally and help it reform its public sector and become more efficient.
This includes visits from experts from Sweden and the Netherlands to help with tax collection and from France to help track rich individuals.
Mr Reichenbach noted that the country could boost its exports by as much as 10% if it brought it standards in line with the rest of Europe's.
Greek customs controls for exports currently take about 20 days, double the EU average, he said.
While he praised the steps Greece had taken, he said that "too much red tape" remained in the country.
He also said that no decision had been taken on whether to send more EU inspectors to monitor the country's finances in the aftermath of the second bailout.